scholarly journals Measuring Stand Tests of a Michell-Banki Waterturbine Prototype, Performedunder Natural Conditions

2018 ◽  
Vol 2018 (2) ◽  
pp. 77-95
Author(s):  
Wojciech Zdrojewski
Keyword(s):  
Test Results ◽  
Test Environment ◽  
Measurement Results ◽  
Water Turbine ◽  
Shaft Power ◽  
Fluent Software ◽  
Numerical Flow Modeling ◽  
New Applications ◽  
Water Turbines ◽  
Flow Devices

Abstract The article presents the result of tests of a single segment of a prototype water turbine, performed in order to determine its shaft power output as a function of rpm, and to verify the declared performance. The results have been compared with the outcomes of numerical calculations performed, for the same conditions, with the use of FLUENT software. The work presents information of crucial importance for presenting the process of testing the piece in question, such as: test environment, properties of the test piece, testing equipment used, as well as the methodology and the course of hydromechanical measurements, along with the characteristics of the results obtained. Then, the measurement results are discussed and analyzed. Conclusions are presented as well. Analysis of the results, taking into consideration the physical image of phenomena occurring in the case of flow-devices, such as water turbines, has made it possible to define other, important characteristics of the turbine, such as: output, shaft torque and efficiency, as a function of rpm and head of turbine. Test results have confirmed the expected mechanical and power-related properties of the turbine and have proved the numerical flow modeling model used effective. A brief description of the prospects concerning new applications of the turbine discussed has been presented as well

Achievements in High Specific-Speed Water Turbines

1934 ◽  
Vol 128 (1) ◽  
pp. 361-407
Author(s):  
A. A. Fulton
Keyword(s):  
Stainless Steel ◽  
Laboratory Tests ◽  
Steady Increase ◽  
Test Results ◽  
Suction Tube ◽  
Generating Sets ◽  
Laboratory Test Results ◽  
Water Turbine ◽  
Specific Speed ◽  
Water Turbines

The steady increase in the capacity of generating sets created a demand for the high specific-speed turbine which was met by several experimenters. “Specific speed” is the speed at which a turbine will run under unit head when developing unit power, and nowadays a “high specific-speed” water turbine denotes one having a runner of the propeller type and a specific speed between 100 and 230 r.p.m. Difficulties were encountered in the development of propeller turbines, especially in connexion with cavitation. Laboratory tests and the use of visual study methods have played an important part in the solution of these difficulties. The method of fixing suction head in conjunction with laboratory test results is explained, and a comparison is made between the various forms of suction tube in use. Much work has been done to overcome the effects of localized cavitation, and stainless steel has been found to be very effective, especially when runners are cast entirely of that material. A method of operation has been developed to dispense with the use of inlet sluice gates in large machines. Several methods in use for operating the movable runner blades are described. The introduction of the high specific-speed turbine has led to a large increase in the number of automatic stations. The great size attained by these turbines has entailed the construction of equally large generators, the development of which has had its own problems.

Manipulate Me

2020 ◽  
Vol 36 (4) ◽  
pp. 554-562
Author(s):  
Alica Thissen ◽  
Frank M. Spinath ◽  
Nicolas Becker
Keyword(s):  
High School Students ◽  
Spatial Ability ◽  
Convergent Validity ◽  
Item Difficulty ◽  
Test Results ◽  
Response Elimination ◽  
School Students ◽  
Test Environment ◽  
Response Options ◽  
Construction Task

Abstract. The cube construction task represents a novel format in the assessment of spatial ability through mental cube rotation tasks. Instead of selecting the correct answer from several response options, respondents construct their own response in a computerized test environment, leading to a higher demand for spatial ability. In the present study with a sample of 146 German high-school students, we tested an approach to manipulate the item difficulties in order to create items with a greater difficulty range. Furthermore, we compared the cube task in a distractor-free and a distractor-based version while the item stems were held identical. The average item difficulty of the distractor-free format was significantly higher than in the distractor-based format ( M = 0.27 vs. M = 0.46) and the distractor-free format showed a broader range of item difficulties (.02 ≤  pi ≤ .95 vs. .37 ≤  pi ≤ .63). The analyses of the test results also showed that the distractor-free format had a significantly higher correlation with a broad intelligence test ( r = .57 vs. r = .17). Reasons for the higher convergent validity of the distractor-free format (prevention of response elimination strategies and the broader range of item difficulties) and further research possibilities are discussed.

scholarly journals Performance Characteristics in Runner of an Impulse Water Turbine with Splitter Blade

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 303
Author(s):  
Lingdi Tang ◽  
Shouqi Yuan ◽  
Yue Tang ◽  
Zhijun Gao
Keyword(s):  
Energy Conversion ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Experimental Tests ◽  
High Energy ◽  
Negative Energy ◽  
Water Turbine ◽  
Conversion Performance ◽  
Water Turbines ◽  
Current Energy

The impulse water turbine is a promising energy conversion device that can be used as mechanical power or a micro hydro generator, and its application can effectively ease the current energy crisis. This paper aims to clarify the mechanism of liquid acting on runner blades, the hydraulic performance, and energy conversion characteristics in the runner domain of an impulse water turbine with a splitter blade by using experimental tests and numerical simulations. The runner was divided into seven areas along the flow direction, and the power variation in the runner domain was analyzed to reflect its energy conversion characteristics. The obtained results indicate that the critical area of the runner for doing the work is in the front half of the blades, while the rear area of the blades does relatively little work and even consumes the mechanical energy of the runner to produce negative work. The high energy area is concentrated in the flow passage facing the nozzle. The energy is gradually evenly distributed from the runner inlet to the runner outlet, and the negative energy caused by flow separation with high probability is gradually reduced. The clarification of the energy conversion performance is of great significance to improve the design of impulse water turbines.

Application of an Angular Momentum Balance Method for Investigating Numerical Accuracy in Swirling Flow

2003 ◽  
Vol 125 (4) ◽  
pp. 723-730
Author(s):  
H. Nilsson ◽  
L. Davidson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Angular Momentum ◽  
Swirling Flow ◽  
Linear Momentum ◽  
Correct Solution ◽  
Momentum Balance ◽  
Numerical Accuracy ◽  
Water Turbine ◽  
Water Turbines

This work derives and applies a method for the investigation of numerical accuracy in computational fluid dynamics. The method is used to investigate discretization errors in computations of swirling flow in water turbines. The work focuses on the conservation of a subset of the angular momentum equations that is particularly important to swirling flow in water turbines. The method is based on the fact that the discretized angular momentum equations are not necessarily conserved when the discretized linear momentum equations are solved. However, the method can be used to investigate the effect of discretization on any equation that should be conserved in the correct solution, and the application is not limited to water turbines. Computations made for two Kaplan water turbine runners and a simplified geometry of one of the Kaplan runner ducts are investigated to highlight the general and simple applicability of the method.

System design and new applications for atomic force microscope based on tunneling

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542039
Author(s):  
X. Wang ◽  
A. P. Liu ◽  
X. H. Yang
Keyword(s):  
System Design ◽  
Protein A ◽  
Protein Structures ◽  
Human Antibody ◽  
Force Microscopy ◽  
Atomic Force ◽  
Measurement Results ◽  
Original Frame ◽  
New Applications ◽  
Tunnel Microscopy

The design of atomic force microscopy (AFM) with high resolution is introduced in this paper. Mainly, we have developed the system design of the apparatus based on tunneling. AFM.IPC-208B, this kind of apparatus combines scanning tunnel microscopy (STM) and AFM availability, and its lens body with original frame enhances the capability of the machine. In order to analyze the performance of AFM.IPC-208B, as a new tool in the field of Life Science, we make use of the system to study natural mica and molecular protein structures of Cattle-insulin and human antibody immunoglobulin G (IgG) coupled with staphylococcus protein A (SPA). As the results of new applications, the resolution of AFM.IPC-208B is proved to be 0.1 nm, and these nanometer measurement results provide much valuable information for the study of small molecular proteins and HIV experiments.

scholarly journals Dynamic Analysis and Control of an Automatic Transmission for Start-Stop Function and Efficiency Improvement

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Yang Liu ◽  
Shuhan Wang ◽  
Peng Dong ◽  
Xiangyang Xu
Keyword(s):  
Control Strategies ◽  
Automatic Transmission ◽  
Simulation Method ◽  
Transmission Efficiency ◽  
The Novel ◽  
Test Results ◽  
Test Environment ◽  
Pump System ◽  
Oil Pump ◽  
And Control

An electric oil pump (EOP) was integrated into the hydraulic system and an automatic transmission (AT) mechanical oil pump (MOP) was downsized. These processes were performed to combine a start-stop function with the AT and further improve the transmission efficiency. Furthermore, this study established a dynamics model of power loss and leakage of an 8-speed AT; a flow-based control algorithm of the EOP was then developed to realize the start-stop function and support the MOP to meet the flow requirement of the system. Based on a driving simulation method, sizes of the MOP and EOP that ensured optimal fuel economy were selected. A control strategy for the starting clutch was also developed to minimize the starting delay of the test vehicle. A test environment on a rig and prototype vehicle was established to verify the feasibility of the proposed control strategies. The test results indicated that the transmission functioned favorably with the novel two-pump system presented, and a quick and smooth starting performance was achieved when the engine was restarted. The findings in this study are extremely valuable for forward designs of an AT for realizing start-stop function and improving efficiency.

Launching of Ships and Floating Structures from Horizontal Berth by Tipping Table

1998 ◽  
Vol 14 (04) ◽  
pp. 265-276
Author(s):  
Ivo Senjanovic
Keyword(s):  
Structural Dynamics ◽  
Review Paper ◽  
Offshore Structures ◽  
Model Tests ◽  
Full Scale ◽  
Strength Analysis ◽  
Test Results ◽  
Floating Structures ◽  
Measurement Results

This review paper covers extensive investigations which were undertaken in order to verify the idea of launching of ships and other floating structures from a horizontal berth by a set of turning pads. This includes structural dynamics during launching, model tests and strength analysis of the structure and the launching system. The most important results, which were used for the design of the launching system, are presented. The preparation of a barge for side launching is described, and the full-scale measurement results are compared with the test results. The advantages of building ships and offshore structures on a horizontal berth are pointed out in the conclusion.

scholarly journals Design of Monitoring Tool Heartbeat Rate and Human Body Temperature Based on WEB

2018 ◽  
Vol 164 ◽  
pp. 01017 ◽  
Author(s):  
Jalinas ◽  
Wahyu Kusuma Raharja ◽  
Bobby Putra Emas Wijaya
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Human Body ◽  
Average Error ◽  
Web Pages ◽  
Test Results ◽  
Pulse Sensor ◽  
Measurement Results ◽  
Human Body Temperature ◽  
Error Percentage

The heart is one of the most important organs in the human body. One way to know heart health is to measure the number of heart beats per minute and body temperature also shows health, many heart rate and body temperature devices but can only be accessed offline. This research aims to design a heart rate detector and human body temperature that the measurement results can be accessed via web pages anywhere and anytime. This device can be used by many users by entering different ID numbers. The design consists of input blocks: pulse sensor, DS18B20 sensor and 3x4 keypad button. Process blocks: Arduino Mega 2560 Microcontroller, Ethernet Shield, router and USB modem. And output block: 16x2 LCD and mobile phone or PC to access web page. Based on the test results, this tool successfully measures the heart rate with an average error percentage of 2.702 % when compared with the oxymeter tool. On the measurement of body temperature get the result of the average error percentage of 2.18 %.

Numerical Calculation of Unsteady Flow Fields: Feasibility of Applying the Weis-Fogh Mechanism to Water Turbines

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Kideok Ro ◽  
Baoshan Zhu
Keyword(s):  
Unsteady Flow ◽  
Velocity Ratio ◽  
Vortex Method ◽  
Flow Fields ◽  
Maximum Efficiency ◽  
Opening Angle ◽  
Stroke Length ◽  
Water Turbine ◽  
Type Water ◽  
Water Turbines

In this study, a reciprocating-type water turbine model that applies the principle of the Weis-Fogh mechanism was proposed, and the model's unsteady flow field was calculated by an advanced vortex method. The primary conditions were as follows: wing chord C=1, wing shaft stroke length hs=2.5C, and the maximum opening angle of the wing α=36 deg. The dynamic characteristics and unsteady flow fields of a Weis-Fogh type water turbine were investigated with velocity ratios U/V = 1.0 ∼ 3.0. Force coefficients Cu and Cv acting on the wing in the U and V directions, respectively, were found to have a strong correlation each other. The size of a separated region on the back face of the wing increased as the velocity ratio increased and as the wing approached the opposite wall. The rapid drop in Cv during a stroke increased as the velocity ratio increased, and the average Cu and Cv increased as the velocity ratio increased. The maximum efficiency of this water turbine was 14.1% at U/V = 2.0 for one wing.

scholarly journals Hubungan Mean Arterial Pressure (MAP) Dengan Preeklamsia Pada Ibu Hamil Di Puskesmas Bontobangun Kabupaten Bulukumba

2020 ◽  
Vol 5 (2) ◽  
pp. 138-145
Author(s):  
Ely Kurniati ◽  
Rusnawati
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Pregnant Women ◽  
Sampling Method ◽  
Blood Pressure Measurement ◽  
Test Results ◽  
Historical Cohort ◽  
Measurement Results ◽  
History Of ◽  
The Mean

Preeclampsia complicates 4-7% of pregnancies and remains the leading cause of maternal and fetal morbidity and mortality worldwide. Despite improvements in health care over the last decade, preeclampsia remains the second most common cause of maternal mortality in Indonesia. This study aims to determine whether the mean arterial pressure (MAP) is related to the incidence of preeclampsia in pregnant women at the Bontobangun Puskesmas, Bulukumba district for the period 2018 to 2019. This research uses a descriptive-analytic approach with Historical Cohort Studies, namely by looking at the cohort book of the history of blood pressure measurement results for pregnant women at the Bontobangun Public Health Center, Bulukumba Regency for the period 2018 to 2019. Determining the sample using the sampling method taken by purposive sampling. 31 samples of pregnant women who experienced preeclampsia and 31 controls were pregnant women with normal conditions who had certain criteria (matching) with the sample. The results explained that from the paired T-test results, the value of α> 0.037 so that it is said that there is a relationship between mean artery pressure (MAP) and the incidence of preeclampsia in pregnant women at Bontobangun puskesmas for the period 2018-2019.

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